This patch updates diff documentation and usage strings:
- clarify the semantics of -R. It is not "output in reverse";
rather, it is "I will feed diff backwards". Semantically
they are different when -C is involved.
- describe -O in usage strings of diff-* brothers. It was
implemented, documented but not described in usage text.
Also it adds -O to diff-helper. Like -S (and unlike -M/-C/-B),
this option can work on sanitized diff-raw output produced by
the diff-* brothers. While we are at it, the call it makes to
diffcore is cleaned up to use the diffcore_std() like everybody
else, and the declaration for the low level diffcore routines
are moved from diff.h (public) to diffcore.h (private between
diff.c and diffcore backends).
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>